1. Field of Invention
The present invention relates to a touch sensing apparatus, and more particularly to a dual-mode touch sensing apparatus with capacitive and electromagnetic sense technology.
2. Description of Related Art
A dual-mode touch sensing apparatus simultaneously includes a capacitive touch sensing electrode and an electromagnetic touch sensing antenna. When the dual-mode touch sensing apparatus is integrated into a liquid crystal display, the capacitive touch sensing electrode and the electromagnetic touch sensing antenna are disposed in different sides of the Liquid crystal display.
Typically, the electromagnetic sensing antenna is an antenna array formed in a substrate. A control circuit calculates a touch position when a sensing pen touches the electromagnetic sensing antenna. The sensing pen is a transceiver and the substrate with the antenna array is a receiver. When a user uses the sensing pen to touch the substrate, magnetic flux is changed. A control circuit can detect the change of the magnetic flux to calculate the touch position.
Typically, the electromagnetic sensing antenna is adhered to a backside of the liquid crystal display by an adhering process. That is, an additional adhering process is required. It is not beneficial for the cost. Moreover, if the material of the backside board of the liquid crystal display is metal, the sensing of the electromagnetic sensing antenna will be interfered by the metal backside board, thus affecting the sensing operation. On the other hand, the electromagnetic sensing antenna also increases the whole volume of the liquid crystal display.